src/common/color.c

/* Copyright (c) 1991 Regents of the University of California */

#ifndef lint
static char SCCSid[] = "$SunId$ LBL";
#endif

/*
 *  color.c - routines for color calculations.
 *
 *     10/10/85
 */

#include  <stdio.h>

#include  <math.h>

#include  "color.h"

#define  MINELEN        8       /* minimum scanline length for encoding */
#define  MAXELEN        0x7fff  /* maximum scanline length for encoding */
#define  MINRUN         4       /* minimum run length */


char *
tempbuffer(len)                 /* get a temporary buffer */
unsigned  len;
{
        extern char  *malloc(), *realloc();
        static char  *tempbuf = NULL;
        static unsigned  tempbuflen = 0;

        if (len > tempbuflen) {
                if (tempbuflen > 0)
                        tempbuf = realloc(tempbuf, len);
                else
                        tempbuf = malloc(len);
                tempbuflen = tempbuf==NULL ? 0 : len;
        }
        return(tempbuf);
}


fwritecolrs(scanline, len, fp)          /* write out a colr scanline */
register COLR  *scanline;
unsigned  len;
register FILE  *fp;
{
        register int  i, j, beg, cnt;
        int  c2;
        
        if (len < MINELEN | len > MAXELEN)      /* OOBs, write out flat */
                return(fwrite((char *)scanline,sizeof(COLR),len,fp) - len);
                                        /* put magic header */
        putc(2, fp);
        putc(2, fp);
        putc(len>>8, fp);
        putc(len&255, fp);
                                        /* put components seperately */
        for (i = 0; i < 4; i++) {
            for (j = 0; j < len; j += cnt) {    /* find next run */
                for (beg = j; beg < len; beg += cnt) {
                    for (cnt = 1; cnt < 127 && beg+cnt < len &&
                            scanline[beg+cnt][i] == scanline[beg][i]; cnt++)
                        ;
                    if (cnt >= MINRUN)
                        break;                  /* long enough */
                }
                if (beg-j > 1 && beg-j < MINRUN) {
                    c2 = j+1;
                    while (scanline[c2++][i] == scanline[j][i])
                        if (c2 == beg) {        /* short run */
                            putc(128+beg-j, fp);
                            putc(scanline[j][i], fp);
                            j = beg;
                            break;
                        }
                }
                while (j < beg) {               /* write out non-run */
                    if ((c2 = beg-j) > 128) c2 = 128;
                    putc(c2, fp);
                    while (c2--)
                        putc(scanline[j++][i], fp);
                }
                if (cnt >= MINRUN) {            /* write out run */
                    putc(128+cnt, fp);
                    putc(scanline[beg][i], fp);
                } else
                    cnt = 0;
            }
        }
        return(ferror(fp) ? -1 : 0);
}


freadcolrs(scanline, len, fp)           /* read in an encoded colr scanline */
register COLR  *scanline;
int  len;
register FILE  *fp;
{
        register int  i, j;
        int  code, val;
                                        /* determine scanline type */
        if (len < MINELEN | len > MAXELEN)
                return(oldreadcolrs(scanline, len, fp));
        if ((i = getc(fp)) == EOF)
                return(-1);
        if (i != 2) {
                ungetc(i, fp);
                return(oldreadcolrs(scanline, len, fp));
        }
        scanline[0][GRN] = getc(fp);
        scanline[0][BLU] = getc(fp);
        if ((i = getc(fp)) == EOF)
                return(-1);
        if (scanline[0][GRN] != 2 || scanline[0][BLU] & 128) {
                scanline[0][RED] = 2;
                scanline[0][EXP] = i;
                return(oldreadcolrs(scanline+1, len-1, fp));
        }
        if ((scanline[0][BLU]<<8 | i) != len)
                return(-1);             /* length mismatch! */
                                        /* read each component */
        for (i = 0; i < 4; i++)
            for (j = 0; j < len; ) {
                if ((code = getc(fp)) == EOF)
                    return(-1);
                if (code > 128) {       /* run */
                    code &= 127;
                    val = getc(fp);
                    while (code--)
                        scanline[j++][i] = val;
                } else                  /* non-run */
                    while (code--)
                        scanline[j++][i] = getc(fp);
            }
        return(feof(fp) ? -1 : 0);
}


oldreadcolrs(scanline, len, fp)         /* read in an old colr scanline */
register COLR  *scanline;
int  len;
register FILE  *fp;
{
        int  rshift;
        register int  i;
        
        rshift = 0;
        
        while (len > 0) {
                scanline[0][RED] = getc(fp);
                scanline[0][GRN] = getc(fp);
                scanline[0][BLU] = getc(fp);
                scanline[0][EXP] = getc(fp);
                if (feof(fp) || ferror(fp))
                        return(-1);
                if (scanline[0][RED] == 1 &&
                                scanline[0][GRN] == 1 &&
                                scanline[0][BLU] == 1) {
                        for (i = scanline[0][EXP] << rshift; i > 0; i--) {
                                copycolr(scanline[0], scanline[-1]);
                                scanline++;
                                len--;
                        }
                        rshift += 8;
                } else {
                        scanline++;
                        len--;
                        rshift = 0;
                }
        }
        return(0);
}


fwritescan(scanline, len, fp)           /* write out a scanline */
register COLOR  *scanline;
int  len;
FILE  *fp;
{
        COLR  *clrscan;
        int  n;
        register COLR  *sp;
                                        /* get scanline buffer */
        if ((sp = (COLR *)tempbuffer(len*sizeof(COLR))) == NULL)
                return(-1);
        clrscan = sp;
                                        /* convert scanline */
        n = len;
        while (n-- > 0) {
                setcolr(sp[0], scanline[0][RED],
                                  scanline[0][GRN],
                                  scanline[0][BLU]);
                scanline++;
                sp++;
        }
        return(fwritecolrs(clrscan, len, fp));
}


freadscan(scanline, len, fp)            /* read in a scanline */
register COLOR  *scanline;
int  len;
FILE  *fp;
{
        register COLR  *clrscan;

        if ((clrscan = (COLR *)tempbuffer(len*sizeof(COLR))) == NULL)
                return(-1);
        if (freadcolrs(clrscan, len, fp) < 0)
                return(-1);
                                        /* convert scanline */
        colr_color(scanline[0], clrscan[0]);
        while (--len > 0) {
                scanline++; clrscan++;
                if (clrscan[0][RED] == clrscan[-1][RED] &&
                            clrscan[0][GRN] == clrscan[-1][GRN] &&
                            clrscan[0][BLU] == clrscan[-1][BLU] &&
                            clrscan[0][EXP] == clrscan[-1][EXP])
                        copycolor(scanline[0], scanline[-1]);
                else
                        colr_color(scanline[0], clrscan[0]);
        }
        return(0);
}


setcolr(clr, r, g, b)           /* assign a short color value */
register COLR  clr;
double  r, g, b;
{
        double  d;
        int  e;
        
        d = r > g ? r : g;
        if (b > d) d = b;

        if (d <= 1e-32) {
                clr[RED] = clr[GRN] = clr[BLU] = 0;
                clr[EXP] = 0;
                return;
        }

        d = frexp(d, &e) * 256.0 / d;

        clr[RED] = r * d;
        clr[GRN] = g * d;
        clr[BLU] = b * d;
        clr[EXP] = e + COLXS;
}


colr_color(col, clr)            /* convert short to float color */
register COLOR  col;
register COLR  clr;
{
        double  f;
        
        if (clr[EXP] == 0)
                col[RED] = col[GRN] = col[BLU] = 0.0;
        else {
                f = ldexp(1.0, (int)clr[EXP]-(COLXS+8));
                col[RED] = (clr[RED] + 0.5)*f;
                col[GRN] = (clr[GRN] + 0.5)*f;
                col[BLU] = (clr[BLU] + 0.5)*f;
        }
}


bigdiff(c1, c2, md)                     /* c1 delta c2 > md? */
register COLOR  c1, c2;
double  md;
{
        register int  i;

        for (i = 0; i < 3; i++)
                if (colval(c1,i)-colval(c2,i) > md*colval(c2,i) ||
                        colval(c2,i)-colval(c1,i) > md*colval(c1,i))
                        return(1);
        return(0);
}
Revision:	2.7
Committed:	Fri Jun 4 14:51:39 1993 UTC (30 years, 11 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.6:	+2 -4 lines
Log Message:	removed incompatible atof(), ldexp() and frexp() defines
#	User	Rev	Content
1	greg	1.14	/* Copyright (c) 1991 Regents of the University of California */
2	greg	1.1
3			#ifndef lint
4			static char SCCSid[] = "$SunId$ LBL";
5			#endif
6
7			/*
8			* color.c - routines for color calculations.
9			*
10			* 10/10/85
11			*/
12
13			#include <stdio.h>
14
15	greg	2.7	#include <math.h>
16
17	greg	1.1	#include "color.h"
18
19	greg	1.14	#define MINELEN 8 /* minimum scanline length for encoding */
20	greg	2.6	#define MAXELEN 0x7fff /* maximum scanline length for encoding */
21	greg	1.14	#define MINRUN 4 /* minimum run length */
22
23	greg	2.4
24	greg	1.14	char *
25			tempbuffer(len) /* get a temporary buffer */
26			unsigned len;
27			{
28			extern char malloc(), realloc();
29			static char *tempbuf = NULL;
30	greg	2.5	static unsigned tempbuflen = 0;
31	greg	1.14
32			if (len > tempbuflen) {
33			if (tempbuflen > 0)
34			tempbuf = realloc(tempbuf, len);
35			else
36			tempbuf = malloc(len);
37			tempbuflen = tempbuf==NULL ? 0 : len;
38			}
39			return(tempbuf);
40			}
41
42
43	greg	1.1	fwritecolrs(scanline, len, fp) /* write out a colr scanline */
44			register COLR *scanline;
45	greg	2.2	unsigned len;
46	greg	1.1	register FILE *fp;
47			{
48	greg	1.14	register int i, j, beg, cnt;
49			int c2;
50	greg	1.1
51	greg	2.5	if (len < MINELEN \| len > MAXELEN) /* OOBs, write out flat */
52	greg	1.14	return(fwrite((char *)scanline,sizeof(COLR),len,fp) - len);
53	greg	2.2	/* put magic header */
54			putc(2, fp);
55	greg	1.14	putc(2, fp);
56			putc(len>>8, fp);
57			putc(len&255, fp);
58			/* put components seperately */
59			for (i = 0; i < 4; i++) {
60			for (j = 0; j < len; j += cnt) { /* find next run */
61			for (beg = j; beg < len; beg += cnt) {
62			for (cnt = 1; cnt < 127 && beg+cnt < len &&
63			scanline[beg+cnt][i] == scanline[beg][i]; cnt++)
64			;
65			if (cnt >= MINRUN)
66			break; /* long enough */
67	greg	1.1	}
68	greg	1.15	if (beg-j > 1 && beg-j < MINRUN) {
69			c2 = j+1;
70			while (scanline[c2++][i] == scanline[j][i])
71			if (c2 == beg) { /* short run */
72			putc(128+beg-j, fp);
73			putc(scanline[j][i], fp);
74			j = beg;
75			break;
76			}
77			}
78			while (j < beg) { /* write out non-run */
79	greg	1.14	if ((c2 = beg-j) > 128) c2 = 128;
80			putc(c2, fp);
81			while (c2--)
82			putc(scanline[j++][i], fp);
83			}
84			if (cnt >= MINRUN) { /* write out run */
85			putc(128+cnt, fp);
86			putc(scanline[beg][i], fp);
87			} else
88			cnt = 0;
89			}
90	greg	1.1	}
91			return(ferror(fp) ? -1 : 0);
92			}
93
94
95	greg	1.14	freadcolrs(scanline, len, fp) /* read in an encoded colr scanline */
96	greg	1.1	register COLR *scanline;
97			int len;
98			register FILE *fp;
99			{
100	greg	1.14	register int i, j;
101	greg	2.6	int code, val;
102	greg	1.14	/* determine scanline type */
103	greg	2.5	if (len < MINELEN \| len > MAXELEN)
104	greg	1.14	return(oldreadcolrs(scanline, len, fp));
105			if ((i = getc(fp)) == EOF)
106			return(-1);
107			if (i != 2) {
108			ungetc(i, fp);
109			return(oldreadcolrs(scanline, len, fp));
110			}
111			scanline[0][GRN] = getc(fp);
112			scanline[0][BLU] = getc(fp);
113			if ((i = getc(fp)) == EOF)
114			return(-1);
115			if (scanline[0][GRN] != 2 \|\| scanline[0][BLU] & 128) {
116			scanline[0][RED] = 2;
117			scanline[0][EXP] = i;
118			return(oldreadcolrs(scanline+1, len-1, fp));
119			}
120			if ((scanline[0][BLU]<<8 \| i) != len)
121			return(-1); /* length mismatch! */
122			/* read each component */
123			for (i = 0; i < 4; i++)
124			for (j = 0; j < len; ) {
125			if ((code = getc(fp)) == EOF)
126			return(-1);
127			if (code > 128) { /* run */
128	greg	2.6	code &= 127;
129			val = getc(fp);
130			while (code--)
131			scanline[j++][i] = val;
132	greg	1.14	} else /* non-run */
133			while (code--)
134			scanline[j++][i] = getc(fp);
135			}
136			return(feof(fp) ? -1 : 0);
137			}
138
139
140			oldreadcolrs(scanline, len, fp) /* read in an old colr scanline */
141			register COLR *scanline;
142			int len;
143			register FILE *fp;
144			{
145	greg	1.1	int rshift;
146			register int i;
147
148			rshift = 0;
149
150			while (len > 0) {
151			scanline[0][RED] = getc(fp);
152			scanline[0][GRN] = getc(fp);
153			scanline[0][BLU] = getc(fp);
154			scanline[0][EXP] = getc(fp);
155			if (feof(fp) \|\| ferror(fp))
156			return(-1);
157			if (scanline[0][RED] == 1 &&
158			scanline[0][GRN] == 1 &&
159			scanline[0][BLU] == 1) {
160			for (i = scanline[0][EXP] << rshift; i > 0; i--) {
161			copycolr(scanline[0], scanline[-1]);
162			scanline++;
163			len--;
164			}
165			rshift += 8;
166			} else {
167			scanline++;
168			len--;
169			rshift = 0;
170			}
171			}
172			return(0);
173			}
174
175
176			fwritescan(scanline, len, fp) /* write out a scanline */
177			register COLOR *scanline;
178			int len;
179	greg	1.14	FILE *fp;
180	greg	1.1	{
181	greg	1.14	COLR *clrscan;
182			int n;
183			register COLR *sp;
184			/* get scanline buffer */
185			if ((sp = (COLR )tempbuffer(lensizeof(COLR))) == NULL)
186			return(-1);
187			clrscan = sp;
188			/* convert scanline */
189			n = len;
190			while (n-- > 0) {
191			setcolr(sp[0], scanline[0][RED],
192	greg	1.1	scanline[0][GRN],
193			scanline[0][BLU]);
194			scanline++;
195	greg	1.14	sp++;
196	greg	1.1	}
197	greg	1.14	return(fwritecolrs(clrscan, len, fp));
198	greg	1.1	}
199
200
201			freadscan(scanline, len, fp) /* read in a scanline */
202			register COLOR *scanline;
203			int len;
204	greg	1.14	FILE *fp;
205	greg	1.1	{
206	greg	1.14	register COLR *clrscan;
207
208			if ((clrscan = (COLR )tempbuffer(lensizeof(COLR))) == NULL)
209			return(-1);
210			if (freadcolrs(clrscan, len, fp) < 0)
211			return(-1);
212			/* convert scanline */
213			colr_color(scanline[0], clrscan[0]);
214			while (--len > 0) {
215			scanline++; clrscan++;
216			if (clrscan[0][RED] == clrscan[-1][RED] &&
217			clrscan[0][GRN] == clrscan[-1][GRN] &&
218			clrscan[0][BLU] == clrscan[-1][BLU] &&
219			clrscan[0][EXP] == clrscan[-1][EXP])
220			copycolor(scanline[0], scanline[-1]);
221			else
222			colr_color(scanline[0], clrscan[0]);
223	greg	1.1	}
224			return(0);
225			}
226
227
228			setcolr(clr, r, g, b) /* assign a short color value */
229			register COLR clr;
230			double r, g, b;
231			{
232			double d;
233			int e;
234
235			d = r > g ? r : g;
236			if (b > d) d = b;
237
238	greg	1.4	if (d <= 1e-32) {
239	greg	1.1	clr[RED] = clr[GRN] = clr[BLU] = 0;
240			clr[EXP] = 0;
241			return;
242			}
243
244			d = frexp(d, &e) * 256.0 / d;
245
246			clr[RED] = r * d;
247			clr[GRN] = g * d;
248			clr[BLU] = b * d;
249			clr[EXP] = e + COLXS;
250			}
251
252
253			colr_color(col, clr) /* convert short to float color */
254			register COLOR col;
255			register COLR clr;
256			{
257	greg	1.6	double f;
258	greg	1.1
259			if (clr[EXP] == 0)
260			col[RED] = col[GRN] = col[BLU] = 0.0;
261			else {
262	greg	1.2	f = ldexp(1.0, (int)clr[EXP]-(COLXS+8));
263	greg	1.1	col[RED] = (clr[RED] + 0.5)*f;
264			col[GRN] = (clr[GRN] + 0.5)*f;
265			col[BLU] = (clr[BLU] + 0.5)*f;
266			}
267	greg	1.6	}
268
269
270	greg	1.7	bigdiff(c1, c2, md) /* c1 delta c2 > md? */
271			register COLOR c1, c2;
272			double md;
273			{
274			register int i;
275
276			for (i = 0; i < 3; i++)
277			if (colval(c1,i)-colval(c2,i) > md*colval(c2,i) \|\|
278			colval(c2,i)-colval(c1,i) > md*colval(c1,i))
279			return(1);
280			return(0);
281			}